12.4
Terrestrial hydrological states and teleconnections with SST phenomena
J. Sheffield, Princeton University, Princeton, NJ; and G. Goteti, E. F. Wood, and D. P. Lettenmaier
Regional land surface hydrology is influenced by and is itself a feedback to large-scale atmospheric circulation processes. Soil moisture and snow cover extent have a major role in this mechanism, providing reservoirs that govern interactions between the land surface and the atmosphere. The influence of these interactions may reach over great distances in the form of anomalies in sea surface temperatures (SSTs), changes in sea ice and weather patterns. In this study we attempt to identify teleconnections between anomalies in regional land surface hydrological states and SSTs around the globe and whether these are the result of long-term climate oscillations or random events. We use as the basis for this study, a global, 50-year dataset of soil moisture and snow cover extent generated by forcing the Variable Infiltration Capacity (VIC) land surface model with an observation based meteorological dataset and the AVHRR/in-situ based NCEP Reynolds Historical Reconstructed SST dataset. The long-term nature of these datasets enable us to encompass a range of climatic oscillations and variability in hydrological state variables. Snow and soil water storage also play a central role in the occurrence of extreme hydrological events such as large scale floods and droughts. Recent flooding in West Africa and China has caused immense problems to the local population and infrastructure. Long-term droughts in the USA have increased wild fire risk and lowered groundwater levels with implications for water resources. Timely prediction and warning of the possibility of major flooding and long-term drought may help to anticipate and reduce the costs of these hydrologic extremes. We discuss the potential use of relationships between land surface hydrological states and SST anomalies in the prediction of extreme events.
Session 12, General Circulation and Teleconnections
Thursday, 13 February 2003, 11:00 AM-12:00 PM
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